Electronic devices interact, or communicate, with users of the devices by receiving input from the users and providing output to the users. Conventional forms of input include keyboards, mice, and touchscreens. Conventional forms of output include digital displays, toggle lights, and liquid crystal displays (LCDs).
Haptic communication refers to interaction with users by recreating the sense of touch by applying forces, vibrations, or motions to the users. For instance, some smartphones include rotating mass motors that vibrate when users touch screens on the smartphones or when users receive notifications of incoming calls, text messages, or emails. However, those motors cannot localize vibrations to any particular locations of the smartphones. Furthermore, the motors are large and limit the physical dimensions of smartphones. Additionally, the motors consume significant power, particularly in comparison to their functional benefit and to other components in the smartphones.
Capacitive sensing refers to interaction with users based on the body capacitance of users. For instance, when users touch a smartphone touchscreen, sensors underneath the touchscreen detect changes in capacitance from the touch. A processor then correlates the changes in capacitance to locations of the touchscreen. However, capacitive sensing is not able to quantify the pressure from touch. Moreover, capacitive sensors do not combine well with haptic motors because the sensors and motors must be separated physically and because the motors cannot localize vibrations to where the sensors sense touch. Thus, capacitive sensing input cannot correlate well to haptic vibration output.